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I think Mac was making a joke that went over peoples heads when you made the comment it halts a major form of heat loss. As Mac points out, we have to lose some heat to survive... so the joke is to be careful and not get your insulation system so efficient that you die from over-heating from your own body heat. .....

Originally Posted by MacEntyre

Yeah, sorry... joke was a bit dry, and ivory tower like... but based on sound principles.

Warm, breathable, windproof, waterproof, lightweight, inexpensive... we can have some, but not all.

Oh OK, yep it went over my head, I didn't know there was humor in that post, I missed it!

But back to serious- for the moment anyway- I don't think we winter hammock hangers are in much danger of failing to lose enough heat to survive while winter hammocking. But, even though we most likely are still losing some heat through various processes, we do ( or pretty close) totally eliminate that one form of heat loss (evaporative cooling) when using a VB. It's hard to evaporate in a sauna suit!

Do you guys think the benefits of a space blanket are significantly due to blocking radiant heat loss as well as normal VB effects? Or, is it in really mostly due to VB effects?

For I consider that the sufferings of this present time are not worthy to be compared with the glory that is to be revealed to us....that the creation itself also will be set free from its slavery to corruption into the freedom of the glory of the children of God. For we know that the whole creation groans and suffers the pains of childbirth together until now.
Romans 8:18,21-22

Do you guys think the benefits of a space blanket are significantly due to blocking radiant heat loss as well as normal VB effects? Or, is it in really mostly due to VB effects?

If you are talking about in the HH SS where it is placed between the hammock and the open cell foam pad, my guess would be that it is the VB effect. You need a gap, or separation for radiant heat transfer to come into play and if you have that gap you are going to lose the more effective conductive heat transfer mode and have conduction and radiant heat transfer as the heat transfer modes. In that system you are trying to get that ocf pad snug against the bottom of the hammock to eliminate gaps or separation to get the best performance. If you get gaps, you have nothing to lose and may gain a little something if the vapor barrier is also a radiant reflector, like a space blanket... maybe.

Billy, couple of observations on your last. Your friends feet got warm because they were able to retain what little heat was in them via the VB socks. Put VB socks on when you're feet are warm and boy those wool socks will be wet with sweat in no time.

and re the water and windproof layer, if you chose eVent or goretex, or even Parameta (paramo's material) then it will breathe with no problem.

I think the thing here is that we all have different gear and different experiences. Evidntly you are keen on VBs and your experience has led to this. No problem there. For me, I'm still of the view that for a vb to truly work in the way it should, the temperature/conditions window is / has to be very narrow. Its a fine line between it working and it creating its own problem.

Billy, couple of observations on your last. Your friends feet got warm because they were able to retain what little heat was in them via the VB socks. Put VB socks on when you're feet are warm and boy those wool socks will be wet with sweat in no time.

Nick, I don't see how, unless there was a hole in the VB. Those VBs are coated nylon and completely water proof to a fairly high pressure. ( I still use them on occasion after 25 years! ) So I don't know how the sweat is going to get past the VB to the wool socks in order to get them wet. I have used them numerous times myself over the years, always putting them on before my feet are cold. Usually over the thinnest liner socks I can find. Mostly I sleep in them. After 8 plus hours the inner liner socks are usually pretty soaked. But the wool socks that are over the VB socks? Always bone dry.

and re the water and windproof layer, if you chose eVent or goretex, or even Parameta (paramo's material) then it will breathe with no problem.

Well, theoretically they will. I've got a lot of Goretex and various clones, but no Event or Paramo, so I'll have to take your word on that. But many a person has reported over the years that on long and very cold trips, their down- with the most breathable possible nylon shells ( way more breathable than GTX) often loses some loft ( or rarely a lot) even though it never gets wet from the outside. Also they gain weight, a sure sign of water in the down. Again, see the links I posted earlier- about 6 posts back I think- from HF folks posting their own experiences. Including at a recent very cold group hang where one user had a VB between him and his UQ, but the top layers were completely breathable. That was just a short 3 night trip with some Sun available for drying. And he dried his top layers for 4 hours in the Sun, but did saw no need to dry the VB protected layer, because it appeared bone dry. But even after drying 4 hours in the Sun, there was still 2X as much water weight in Non-VB gear. After a week or so of this, there would have been some loft problems most likely. This was likely mostly or completely from condensation inside the most breathable possible shells. When moisture hits a cold enough surface it likely condenses regardless of how breathable.

Here is what is for me some pretty solid evidence: fleece sleeping bibs. Lots of us here have had a lot of trouble with the area of out TQs that is closest to our face getting soaked with condensation. Shug has come up with an idea that lots of folks are using: a piece of fleece with a head hole cut in it is hung from the ridge line, and their heads put through the hole. So this piece of fleece hangs between their mouths/nose and the TQ/hammock. Now what is more breathable than fleece? We all no how useless it is at wind block. You can put a fleece neck gator over your nose and breath right through it. But what happens when their breath hits this extremely breathable but very cold fleece? It condenses and freezes immediately.

I think the thing here is that we all have different gear and different experiences. Evidntly you are keen on VBs and your experience has led to this. No problem there. For me, I'm still of the view that for a vb to truly work in the way it should, the temperature/conditions window is / has to be very narrow. Its a fine line between it working and it creating its own problem.

Well, we do probably have different experiences. But I am not really all that gung Ho VBs. Again, except for the space blanket over my HHSS pad ( and not always then) and occasionally the same inside my PeaPod, I rarely use any VB. It's been a long time since I even used those VB socks we have been discussing. But no matter what the conditions, when I do use them, they make me warmer and my insulation dryer. Because they are waterproof, as WP as my tarp, and even if I sweat a good bit, that water can not reach my insulation. Though in use, if I feel any where near hot enough to sweat, I will either vent as needed or remove any VB. But mostly, I use breathable systems without VB. So they work for me WHEN I use them, but as always HYOH!

I wish Wisenber would chime in with his recent experiences. They were fascinating both in regards to warmth gained and keeping dry insulation.

For I consider that the sufferings of this present time are not worthy to be compared with the glory that is to be revealed to us....that the creation itself also will be set free from its slavery to corruption into the freedom of the glory of the children of God. For we know that the whole creation groans and suffers the pains of childbirth together until now.
Romans 8:18,21-22

OH, Nick a P.S.:
BTW, I do have some things against VB use: assuming I can be warm enough without them and assuming I don't think condensation is going to be serious problem, the main reason not to use them is COMFORT!

A breathable system is just more comfortable to me, not counting a VB under my hammock- I never feel those. But if you mean VB socks or clothing, I always feel wet in them. Because I am, a little bit. Which is kind of scary in the cold, you can't help but think you are going to get cold because you are wet. Even if the opposite is actually true. But I don't like that damp feeling I often get, even if I will put up with it if needed.

The other thing is: sooner or later you probably have to come out of that VB clothing. And that is when you find out just how valuable completely stopping evaporative cooling has been. If you take a VB off in the cold, best get ready for a shocking blast of cold. Much more noticeable than if you are changing clothes without a VB!

And one last thing is user error if some one does not understand VB use. They are probably going to end up with wet insulation, rather than drier insulation.

For I consider that the sufferings of this present time are not worthy to be compared with the glory that is to be revealed to us....that the creation itself also will be set free from its slavery to corruption into the freedom of the glory of the children of God. For we know that the whole creation groans and suffers the pains of childbirth together until now.
Romans 8:18,21-22

Gotcha. I misunderstood about the vb socks. I thought they were going over the wool socks not under. Same point applies though, just that the feet would ultimately get pretty sweaty, just that the wool socks wouldnt get wet.

The eternal problem as you say with any breathable fabric is it being compromised by very wet conditions or very high humidity effectively "blocking" the pores on the outside and rendering the vapour transfer useless. I have a Paramo Adventure smock which I love and use for hiking - yesterday on a 6 hour hike with 4000 feet of ascent, it worked perfectly. Conditions were dry and cool with some wind. I wore a thin wool base layer under it and was getting pretty hot and sweating, but the "pump" liner got the moisture from the wicking layer through the parameta material easily, keeping me totally dry but still warm. Constrast that with last year on a similar hike in the rain when the inside was soaking wet. I had my iphone in the chest pocket and when I got to the top to take a pic with it, it was dripping wet. The rain had blocked the vapour transfer and the moisture was running down the inside and onto the top of my trousers and I was REALLY hot.

I actually think on balance that a UQ with a standard ripstop top layer (closest to the hammock) and something like a parameta fabric under layer would work pretty well (certainly for the UK weather). The problem here is wind blown rain potentially wetting your UQ which means that in poor weather you have to pitch your tarp really low to prevent that, which means its less comfortable getting in and out of the hammock and you cant really hang out in it because there's no room to sit on it and relax due to the close proximity of the tarp.

Gotcha. I misunderstood about the vb socks. I thought they were going over the wool socks not under. Same point applies though, just that the feet would ultimately get pretty sweaty, just that the wool socks wouldnt get wet.

The eternal problem as you say with any breathable fabric is it being compromised by very wet conditions or very high humidity effectively "blocking" the pores on the outside and rendering the vapour transfer useless. I have a Paramo Adventure smock which I love and use for hiking - yesterday on a 6 hour hike with 4000 feet of ascent, it worked perfectly. Conditions were dry and cool with some wind. I wore a thin wool base layer under it and was getting pretty hot and sweating, but the "pump" liner got the moisture from the wicking layer through the parameta material easily, keeping me totally dry but still warm. Constrast that with last year on a similar hike in the rain when the inside was soaking wet. I had my iphone in the chest pocket and when I got to the top to take a pic with it, it was dripping wet. The rain had blocked the vapour transfer and the moisture was running down the inside and onto the top of my trousers and I was REALLY hot.

I actually think on balance that a UQ with a standard ripstop top layer (closest to the hammock) and something like a parameta fabric under layer would work pretty well (certainly for the UK weather). The problem here is wind blown rain potentially wetting your UQ which means that in poor weather you have to pitch your tarp really low to prevent that, which means its less comfortable getting in and out of the hammock and you cant really hang out in it because there's no room to sit on it and relax due to the close proximity of the tarp.

Hey Nick, ia that Paramo stuff a totally synthetic system I have read about that makes no real attempt to block moisture from the outside? But instead counts on it's total breathable and wicking (and hydrophobic?) ability to keep moisture traveling from skin to the outside, and making travel in the other direction very difficult? It's like a UK or Scotland thing? Or is it not that at all?

I have read about that briefly elsewhere, but don't know much about it. But it sounds pretty fascinating, so if you want to maybe give us more info or a complete review of that stuff one of these days, that would be much appreciated. Maybe like compared to the more common waterproof/breathable stuff (GTX/GTX clones/Pertex Endurance/Event etc) we are all so familiar with.
Bill

For I consider that the sufferings of this present time are not worthy to be compared with the glory that is to be revealed to us....that the creation itself also will be set free from its slavery to corruption into the freedom of the glory of the children of God. For we know that the whole creation groans and suffers the pains of childbirth together until now.
Romans 8:18,21-22

Hey Nick, ia that Paramo stuff a totally synthetic system I have read about that makes no real attempt to block moisture from the outside? But instead counts on it's total breathable and wicking (and hydrophobic?) ability to keep moisture traveling from skin to the outside, and making travel in the other direction very difficult? It's like a UK or Scotland thing? Or is it not that at all?

I have read about that briefly elsewhere, but don't know much about it. But it sounds pretty fascinating, so if you want to maybe give us more info or a complete review of that stuff one of these days, that would be much appreciated. Maybe like compared to the more common waterproof/breathable stuff (GTX/GTX clones/Pertex Endurance/Event etc) we are all so familiar with.
Bill

Yes and no (helpful? ). Its highly breathable and like goretex, you have to proof it once in a while with Nikwax TX Direct. It is definitely waterproof from the outside in normal circumstances, but there is this thing that they say which is "water can be pumped away from the inside faster than it can get in". However, it doesnt wholly rely on an inside to out vapour transfer to stop water ingress. If it did, then if you were standing around in the rain it would just go straight through as you're not sweating.

Paramo is a global company, it was launched by the Nikwax guy. Take a look at Paramo.co.uk - it's very popular with hikers as its so warm. As an example you can wear a single layer (thin) thermal top then a paramo lined jacket in all kinds of temperatures and be warm. I've worn mine down to 0F with no issues at all.

The one downside to the clothing is that if you kneel down on wet ground the pressure will force moisture through it. Not so bad if its a kneel, it soon dries out from bodyheat from the inside which then carries the mositure back out again, but if you sit down wearing a pair of paramo trousers you will get a wet behind as it has a low hydrostatic head. Howver, this doesnt mean that you get wet shoulders in heavy rain, it only happens when you put real pressure on it on wet ground/rock etc.

The tops especially are very good. The Velez smock for example is super lightweight and pretty thin. Despite this, with a thin woolpower thermal top under it I didnt need anything else yesterday despite the ambient being about 20F and the wind chill around 10F

The other thing you might find interesting with it is the so called "pump liner". How this works I really don't know, but say you put on a paramo jacket over a soaked through wet top, if you walk for a while your wool top will become dry in about half an hour (depending on body temp, ambient conditions etc). The negative with the gear is that it isnt designed for heavy camp type work ie lots of kneeling down, abrasion, friction and it doesn't like sparks much.

BillyBob58, I am a fan of VB. I read a couple of posts about having wet feet with VB socks. This is actually the DESIRED result. The principal of VB is not to stop perspiration or wetness but to contain and reduce both. Without VB, your body will continue to produce insensible perspiration in cold dry conditions as the skin attempts to reach an equilibrium level of humidity to remain at its natural moisture content. With a VB layer close to your skin, that equilibrium is reached sooner as the humidity level is much higher under the VB layers than the outside relative humidity. This has a twofold benefit. First, your body will not lose heat due to evaporative heat loss. Just as the evaporation of perspiration cools you when it's hot, it continues to do so when it's cold. The second benefit is the reduced level of insensitive perspiration results by its very nature in a greater hydration level. The more hydrated you are, the more efficiently your body can generate and regulate temperature. This is true whether it is hot or cold.
There's good reason for the US military cold extreme cold weather boots being VB. During the Korean Conflict, it was discovered that having breathable materials that could absorb perspiration resulted in a much higher incidence of frost bite. The "Mickey Mouse boots" are essentially a thick layer of felt enclosed in rubber. The rubber does not allow the felt to become wet or the tissue in the feet to become dry enough to freeze. These VB boots essentially removed frostbite from the picture, but replaced it with trench foot. The balance was found by using VB boots while removing them and drying the feet several times each day.

My practical experience with VB is that it can offer limited yet tangible benefits above or near freezing and substantial benefits well below freezing. The VB gear I use is clothing rather than space blankets and such. This allows me to put my normal clothing over the VB layers to achieve better results than wearing less clothing and having a VB layer outside of it. The clothing I use are Warmlite socks, Warmlite shirt and non-breathable rain pants. I do wear a thin set of long johns under the rain pants, the other articles of clothing are next to skin. Over those layers I wear my normal fleece pants, a thick pair of wool socks and some form of sweater (when well below freezing).
The results have been my down remaining much dryer while getting a good 10-15 degrees F more warmth than I would normally expect from gear that I had used in similar conditions. This past January, I was able to take a 20 F rated UQ and a 20 F rated TQ down below zero without getting cold. I did bail out on the second night when the temps hit -12 F.

I've also used VB while hiking. I've found that experience to be pretty unmanageable except for socks. Having VB socks on during cold weather hiking keeps my feet much warmer and also prevents my boots from freezing at night as they have not been subjected to the sweat.

Yes and no (helpful? ). Its highly breathable and like goretex, you have to proof it once in a while with Nikwax TX Direct. It is definitely waterproof from the outside in normal circumstances, but there is this thing that they say which is "water can be pumped away from the inside faster than it can get in". However, it doesnt wholly rely on an inside to out vapour transfer to stop water ingress. If it did, then if you were standing around in the rain it would just go straight through as you're not sweating.

Paramo is a global company, it was launched by the Nikwax guy. Take a look at Paramo.co.uk - it's very popular with hikers as its so warm. As an example you can wear a single layer (thin) thermal top then a paramo lined jacket in all kinds of temperatures and be warm. I've worn mine down to 0F with no issues at all.

The one downside to the clothing is that if you kneel down on wet ground the pressure will force moisture through it. Not so bad if its a kneel, it soon dries out from bodyheat from the inside which then carries the mositure back out again, but if you sit down wearing a pair of paramo trousers you will get a wet behind as it has a low hydrostatic head. Howver, this doesnt mean that you get wet shoulders in heavy rain, it only happens when you put real pressure on it on wet ground/rock etc.

The tops especially are very good. The Velez smock for example is super lightweight and pretty thin. Despite this, with a thin woolpower thermal top under it I didnt need anything else yesterday despite the ambient being about 20F and the wind chill around 10F

The other thing you might find interesting with it is the so called "pump liner". How this works I really don't know, but say you put on a paramo jacket over a soaked through wet top, if you walk for a while your wool top will become dry in about half an hour (depending on body temp, ambient conditions etc). The negative with the gear is that it isnt designed for heavy camp type work ie lots of kneeling down, abrasion, friction and it doesn't like sparks much.

Thanks, Nick! I will check out that link, this stuff is very interesting. The Nikwax guy, eh? Very interesting! I have never even seen this stuff.

Originally Posted by wisenber

BillyBob58, I am a fan of VB. I read a couple of posts about having wet feet with VB socks. This is actually the DESIRED result. The principal of VB is not to stop perspiration or wetness but to contain and reduce both. Without VB, your body will continue to produce insensible perspiration in cold dry conditions as the skin attempts to reach an equilibrium level of humidity to remain at its natural moisture content. With a VB layer close to your skin, that equilibrium is reached sooner as the humidity level is much higher under the VB layers than the outside relative humidity. This has a twofold benefit. First, your body will not lose heat due to evaporative heat loss. Just as the evaporation of perspiration cools you when it's hot, it continues to do so when it's cold. The second benefit is the reduced level of insensitive perspiration results by its very nature in a greater hydration level. The more hydrated you are, the more efficiently your body can generate and regulate temperature. This is true whether it is hot or cold.
There's good reason for the US military cold extreme cold weather boots being VB. During the Korean Conflict, it was discovered that having breathable materials that could absorb perspiration resulted in a much higher incidence of frost bite. The "Mickey Mouse boots" are essentially a thick layer of felt enclosed in rubber. The rubber does not allow the felt to become wet or the tissue in the feet to become dry enough to freeze. These VB boots essentially removed frostbite from the picture, but replaced it with trench foot. The balance was found by using VB boots while removing them and drying the feet several times each day.

My practical experience with VB is that it can offer limited yet tangible benefits above or near freezing and substantial benefits well below freezing. The VB gear I use is clothing rather than space blankets and such. This allows me to put my normal clothing over the VB layers to achieve better results than wearing less clothing and having a VB layer outside of it. The clothing I use are Warmlite socks, Warmlite shirt and non-breathable rain pants. I do wear a thin set of long johns under the rain pants, the other articles of clothing are next to skin. Over those layers I wear my normal fleece pants, a thick pair of wool socks and some form of sweater (when well below freezing).
The results have been my down remaining much dryer while getting a good 10-15 degrees F more warmth than I would normally expect from gear that I had used in similar conditions. This past January, I was able to take a 20 F rated UQ and a 20 F rated TQ down below zero without getting cold. I did bail out on the second night when the temps hit -12 F.

I've also used VB while hiking. I've found that experience to be pretty unmanageable except for socks. Having VB socks on during cold weather hiking keeps my feet much warmer and also prevents my boots from freezing at night as they have not been subjected to the sweat.

Thanks Wisenber, I knew you had had a lot more recent real world experience than I had. At least with VB clothing, though I do use a VB in the form of the SB only between the hammock and under insulation, at least with some gear, some times. And even less frequently, VB socks.

I am impressed with you making do with - and being ok - a 20F tq/uq below zero while STILL having much drier down. Those are the very conditions where you would potentially have the most condensation in the outer inches of the quilts, when body vapor hits those increasingly cold down/air pockets and finally the outer shell. I'm sure many of us( I have) have awakened to find our sleeping bag shells covered with frost, even when there was no frost on the ground ( very low humidity western conditions) and no rain or drizzle. The trouble with that is, there is no reason to think that frost is on the outside of the shell only. As it happened as our body vapor finally got far enough away from our body to reach dew point.

For I consider that the sufferings of this present time are not worthy to be compared with the glory that is to be revealed to us....that the creation itself also will be set free from its slavery to corruption into the freedom of the glory of the children of God. For we know that the whole creation groans and suffers the pains of childbirth together until now.
Romans 8:18,21-22